The advantages of using such fluids in various applications, and also some disadvantages, have been described in an article in the September/October 1981 Issue of Fluid and Lubricant Ideas starting at page 6. This article mentions the lower cost, better heat transfer characteristics, reduced environmental risk and improved fire resistant properties which high water based fluids exhibit. The use of such fluids also removes the dependency on possibly unreliable mineral oil supplies.
Various patents describe compositions useful in such fluids. See for example United Kingdom published application Nos. 2031908 and 2032951 (Lubrizol), European published applications Nos. 0007567 (Theunissen) and 0024848 (Mobil) and U.S. Pat. Nos. 4,257,902 (Singer), 4,138,346 (BASF) and 4,151,099 (BASF).
It is an object of this invention to provide a method of preparing a concentrate for a high water based hydraulic fluid and a concentrate prepared by that method and fluid prepared from that concentrate.